1. Field of the Invention
The invention relates to a folding condenser for a microscope.
2. Discussion of Related Art
In the case of microscopes having a turret for receiving objectives with different magnification, these objectives are brought into the effective position alternately one after the other. However, rapid switching between these objectives also requires a corresponding adaptation of the illumination with respect to the aperture and the illuminated field. According to German patent document 2,116,625, this adaptation is achieved by a condenser in which there is provided not only a fixed basic condenser but also additional condenser lenses which can be switched into the path of the illuminating beam. These condenser lenses are connected to one another via a linkage, so that various switching positions permit a rapid adaptation of the illumination after a change of objective.
German patent document 2,626,864 discloses a further microscope universal condenser with fixed lens elements and with additional forcibly coupled lens elements, arranged in front of and behind the fixed part in the direction of the light. A lens element provided underneath the fixed lens is arranged in a swivel arm, the direction of movement of which is designed to be perpendicular to the optical axis. A further lens element is arranged on a carriage above the fixed lens and is moved perpendicularly to the optical axis and tangentially to the direction of movement of the second lens element. By means of a complex mechanical shifting linkage, the swivel movement of the arm is transferred by forced coupling into a linear movement of the carriage.
In known devices for exact forced coupling of the individual lens elements, great mechanical complexity is present. Due to the complicated mechanical guidance, the free working distance between the fixed lens and the lens elements to be switched is also small. The insertion of additional optical components for influencing the path of the illuminating beam is made more difficult as a result. Since the condenser head moved on the carriage is arranged very closely underneath the microscope stage, a corresponding recess must be provided here.